Broad wavenumber turbulence measurement in the same region on EAST

Abstract

Future burning plasma in magnetic confinement fusion devices necessitates diagnostic for measuring broad wavenumber turbulence. The CO2 laser Collective Thomson Scattering (CO2-CTS) system on EAST is designed mainly for electron-scale turbulence measurements. In order to extend the capability to detect ion-scale turbulence, the key challenges of light separation and signal detection have been successfully addressed by the construction of the Extremely-small-angle CO2-CTS (E-CTS) diagnostic. This paper employs the CO2-CTS in conjunction with the E-CTS, enabling the simultaneous monitoring of turbulence (0.5<kθρs <5) over a broader wavenumber range (k~5-30 cm-1) within the gradient region (ρ~0.4-0.8). The application of E-CTS studies the characteristics of multi-scale turbulence, including turbulence correlation and dispersion relations. This advancement will significantly enrich our experimental comprehension of tokamak turbulence.